The invention relates to the technical field of bridge erecting construction equipment, in particular to a tunnel-free girder erecting method. The tunnel-free girder erecting method comprises the following steps that a to-be-erected box girder is connected to a lifting device of a girder transporting vehicle, and the girder transporting vehicle moves towards a bridge erecting machine; a lifting bracket of the girder transporting vehicle is connected to a hoisting trolley of the bridge erecting machine, and a front vehicle of the girder transporting vehicle is driven to move upwards; the hoisting trolley and a rear vehicle of the girder transporting vehicle jointly drive the girder transporting vehicle to overall move forwards; the to-be-erected box girder falls on an erected girder span, and the hoisting trolley and the rear vehicle jointly drive the girder transporting vehicle to overall move rearwards; connecting between the lifting bracket and the hoisting trolley is relieved, and meanwhile, the front vehicle is driven to move downwards; after two lower transverse beams on rear supporting legs of the bridge erecting machine move towards each other by a certain distance, and the front vehicle of the girder transporting vehicle is driven to move upwards until supporting points of the lower transverse beams fall on a web of the erected girder span; and the to-be-erected box girder is connected to the hoisting trolley for girder erecting operation. According to the tunnel-free girder erecting method, operation is convenient and quick, and the whole process is quick and efficient.